A. Objective The overall objective of this core facility is to provide placental tissues and purified cytotrophoblast (CTB) cells from abnormal term/preterm and 1st trimester pregnancies to the three projects in this Program grant application. DMA from these placental tissues and CTB cells, as well as from normal term placentas collected in Kansas, will be genotyped in the Core for polymorphisms in HLA-G (Project I, II and Project III), in LILRB1 and LILRB2 (Project I), and in PDCD1 (the gene encoding PD-1) and B7H1 (Project II). The rationale for studying polymorphisms in these genes is provided in the individual projects.